1. Field of the Invention
The present invention is related to a packaging method of semiconductor, more particularly, to a package method and a structure of dies rearrangement by a redistribution layer process to form a module with package body.
2. Description of the Prior Art
Miniaturized semiconductor dice has been a trend for its various functions. These semiconductor dies should be provided with more and more I/O pads within a smaller region, so the density of metal pins raises. Thus, the package technology of lead frame has been replaced by the technology of ball grid array (BGA). It is advantageous for BGA to provide more compact density and have solder less subject to damage and distorted.
With 3C products in fashion, such as cell phone, PDA or iPod, these 3C products are equipped with at least one systemic chip within a smaller volume. A wafer level package (WLP) has been developed to packaging a wafer before sawing. U.S. Pat. No. 5,323,051 discloses one kind of wafer level package. However, for WLP, the increasing number and the reduced pitches of the bonding pads result in signal coupling and noise. In addition, the reliability of package may be reduced because of the reduced pitches. Thus, WLP aforementioned may not satisfy the design of smaller dies.
For resolving the issue, U.S. Pat. No. 7,196,408 teaches a method for the semiconductor process. A plurality of good dies is after tested and sawed rearranged on another substrate for the sequential packaging process. Those rearranged dies have wider pitches for the suitable distribution of bonding pads on the dies, such as using fan out technology. Such a method may resolve the issues of signal coupling and noise caused by small pitches.
However, for the semiconductor chip with smaller and thinner packaging structure, before the wafer saw, the wafer may be processed by a thinning process, such as thinning the wafer in the thickness of 2 to 20 mils by backside lapping. Then, the wafer is sawed to become dice units. Those thinned dies are rearranged on another substrate. Then, a molding process is applied on those thinned dies to form a molding structure. Because both the dies and the molding structure are thin very much, the stress from the molding structure itself would cause curl after the substrate is separated from the molding structure. The curl of the molding structure may make a sequential saw process difficult.
Accordingly, the present invention provides a packaging method for dies rearrangement to efficiently resolve the issue of curl on a molding package.